Why is my friend being repeatedly rejected for a DTV application in Thailand?

I've been trying to help my friend with his DTV application after he was rejected by Jakarta back in November (I was approved by them a week after his initial rejection).

I reviewed his docs, and while technically he met all of the conditions there were a couple of gaps which may have given them some doubt.

I then helped him to ensure all the docs went above and beyond to satisfy all of the visa conditions, and provided some extra information to support the application such as a cover letter.

He's applying for the workcation route, as a remote employee from the UK.

He's been working for the company for over a decade and after a sabbatical he re-joined as a remote employee in November to continue working in Thailand.

We provided a confirmation of employment letter, a separate letter from the directors confirming his right to work remotely from Thailand.

He has provided 3 months of bank statements which show over 600k THB each month, and included 4 payslips from his company which correlate to transactions on the statements.

Provided all the usual proof of location, passport copy including entry stamps/visa's to the applying country and his latest exit stamp from Thailand.

We also added a cover letter to explain all of the above.

He was yet again rejected by Jakarta 2 months after the 1st try. and has now been rejected again by Hanoi.

Obviously without an explanation on all 3 rejections - why could they keep on rejecting him?